Process for the manufacture of unsaturated aldehydes



Patented Sept. 8, 1942 UNITED .STATESQPATENT OFFICE PROCESS FOR THEMANUFACTURE OF UNSATURATED ALDEHYDES Joseph H. Brant, Kingsport, Tenn,assignor to Eastman Kodak Company, Rochester, N. Y., 3 a corporation ofNew Jersey N 6 Drawing. Application August 11, 1938, Serial No. 224,358

g 7 Claims. -(01. 260-601l CH2=CH.CHO.

This application is an improvement invention over that shown in allowedGallagher and .Hasche application Serial No. 88,821, filed July 3,

As pointed out in the aforementioned application, unsaturated aliphaticaldehydes and, in particular, acrolein, have a number of uses.

These organic compounds may be converted to other chemical products. Forexample, acrolein may be converted to propionic aldehyde in accordancewith the procedure set forth in Gallagher and Hasche copendingapplication Serial No. 88,822, entitled "improved Method for themanufacture of propionic aldehyde, now Patent No. 2,150,158. Also,acrolein may serve as a source of propionic aldehyde for the productionof-propionic acid and employ the oxidation procedure described in Haschecopending application No. 34,215 of August 1, 1935.

Liquid phase processes, known as aldol condensation have been carriedout in the prior art, wherein a single aldehyde combines with itself.However, prior to Gallagher and Hasche's invention, few, if any, methodshave been developed for the direct manufacture of the unsaturatedaldehydes and in particular unsaturated aldehydes containing an oddnumber of carbon atoms, with which the present invention is concerned.

I have found an improved method and catalyst for the manufacture ofunsaturated aliphatic aldehydes, and in particular unsaturated aldehydescontaining an odd number of carbon atoms in the molecule, such asacrolein.

I have found that two different, aldehydesmay be caused to readilycombine to produce an unsaturated aldehyde containing a number of carbonatoms equal to the sum of two aldehyde re- 'tively high yields.

actants by carrying out the reaction under the conditions hereindescribed.

This invention has for an object to provide'a particularly effectiveprocess for the combination of two different aliphatic aldehydes toproduce an unsaturated aliphatic aldehyde in rela- Another object is toprovide a process for the production of unsaturated aliphatic aldehydescontaining an odd number of carbon atoms in the molecule. A furtherobject is to improve and expedite the reaction of two differentaldehydes in the vapor phase.

A further object is to provide catalytic procedure particularly adaptedfor the reaction of the one carbon aldehyde, formaldehyde, with anotheraldehyde. Another object is to provide catalytic procedure particularlyadapted for reacting formaldehyde (formalin) or other source thereof,with one or more aldehydes such as acetaldehyde, propionaldehyde and'butyraldehyde. Still another object is to provide a catalystparticularly adapted for the production of unsaturated aliphaticaldehydes. A still further object is to provide a novel catalyst andprocess particularly adapted for the production of unsaturated aliphaticaldehyde such as acrolein, a-methacrolein, a-ethacrolein and the like.

Still another object is to provide novel catalysts and catalyst supportsparticularly adapted for use in processes involving the reaction ofaldehydes containing a dilferent number of carbon atoms in the molecule.

Other objects will appear hereinafter.

I have found that highly desirable results 'may be obtained bycatalytically reacting formaldehyde and acetaldehyde (or other aldehyde)in the presence of a catalyst containing lead and otherwise inaccordance with the procedure set forth herein. 1

My process may be carried out in any suitable apparatus, as for example,the apparatus shown in Gallagher andHasche Patent No. 2,150,158. Asuitable apparatus would comprise two containers, namely, separatecontainers for each of the different aldehydes to be reacted. Conduitswould lead from these containers to vaporizing or mixing equipment whichis in turn connected with a catalyst chamber. The catalyst chamber couldbe heated in a conventional manner electrically, or by gas flame orother procedure. The catalyst chamber would be connected withcondensers, hydrogenation equipment, distillation units or other typeapparatus. I

The catalyst chamber would be filled with *my novel catalyst, which Ihave found to be parquite satfifactory. Preferablyf, the lead salts 10'would be in combination with a silica gel, alumina gel, or the like,although other suitable chamber charged with my novel lead catalyst. Thetemperature of the catalyst chamber and reaction was maintained atgreater than 220 C. and preferably during the greater part of the run ataround 290-320 C. High yields of the unsaturated aldehyde, acrolein,were obtained in the products issuing from the catalyst chamber.

Similar runs were conducted with vaporous mixtures comprisingformaldehyde and other allphatic aldehydes such as propionic aldehydeand butyraldehyde. High yields of the corresponding ti -substitutedunsaturated aldehydes were obmaterials might be employed, such asactivated tained.

carbon, magnesium oxide, or the like. An

For a more complete understanding of my inamount of lead salts usuallyaround 10% of the 15 vention, further reference is made to thefollowtotal catalyst (catalyst plus catalyst support) is ing exampleswhich are set forth in tabular form:

Temp. Feed ratio mlein B see Percent Catalyst m GHQ/H rate... View.2529...

310 0. 28 15. 2 1, 220 09. 5 811108 181....- 1 P1) A0 292 0. 25 15. 9514 73. ..-.-d0 D0. $2 0. 21 11. 9 404 57- 2 .(10 10% Pbsol. 290 0. 218. 42 1. 278 42. 7 A110: 10% P1) (OAOM. 292 0.25 10.8 1,290 40.3.(10..... 10% Pb 804. 284 0. 25 18. 2 865 82. 3 Silica $61.... 10% P1)(0A0)!- 295 0. 25 17. 1 1, 121 82. 2 .d0 D0. 297 0. 303 13.5 1, 125 64.0 d0 10% Pb (Noah. 295 0. 25 11. 7 1, 231 53- 0 DQ011150. 10% P1) (OAQI.300 0.25 l2. 9 l, 29 58. 4 Super Z D Do. 300 0. 25 12. 6 1, 212 61. 6A1201 10% P1) 0104. 300 0. 45 16. 945 40. 5 Silica E91.-. 5% Pb. 3000.45 16.6 945 49.0 do Do. 305 0. 17. 2 955 50. 0 5% PD (OAKM. 295 0. 4517. 3 935 43. 5 2.5% Pb (OAOh.

suflicient. However, othe amounts from V2% up 5 In the preceding tablesthe materials Zeodur,

to 35% or 40% could be employed, but do not represent, my preferredembodiment.

The catalyst may be made by the following procedure- Approximately 100g. of silica gel, alumina gel, or other material to comprise part of thecatalyst was placed in a container. To this material was added an acidsolution prepared by incorporating approximately 10 g. of a leadcompound such as litharge (PhD) in an aqueous acetic acid solutioncomprising approximately one part by volume acetic'acidto 2-3 parts byvolume of water. The excess liquid may be removed by heating togethenifdesired, with the application of reduced pressure.

The silica gel, alumina gel or other material containing lead saltsprepared in accordance with the preceding paragraph was then treatedwith a mixture of aqueous sulphuric acid (10 g. of sulphuric aciddiluted to 30 cc. with water). By this procedure the lead acetate werecompletely converted to the corresponding sulphates, being precipitatedon or within the pores of the supporting material.

As an alternative procedure, the silica gel, alumina gel or othermaterial may be first treated with aqueous sulphuric acid. To thissulphuric acid treated material may then be added the aqueous aceticacid solution resulting from dissolving the lead salt in the aceticacid. satisfactory catalyst is likewise produced by this procedure.

I have also found that an excellent catalyst is a mixture of 75% byweight of lead chromate and 25% of powdered silica gel, pressing themixture into cakes or pellets.

Similar procedure may be followed for preparing catalysts'of other leadsalts.

A vaporous mixture of formaldehyde with acetaldehyde was obtained andthis mixture Super Zeodur, and Decalso are commercially availablesubstances having compositions somewhat as follows:

In my process it is possible to use acetaldehyde from various sources.For example, the acetaldehyde may be obtained synthetically fromacetylene. The acetylene may be produced from calcium carbide, crackinghydrocarbons or the decomposition of hydrocarbons in an electric arc.The acetaldehyde may also be obtained from ethyl alcohol.

Likewise, various sources of formaldehyde may be employed. Sincerelatively pure formaldehyde boils at approximately 2l C., formalin,which contains around 40% of formaldehyde, the remainder beingprincipally methyl alcohol and water, is an easier source offormaldehyde to work with. The methyl alcohol content of the formalindoes not interfere with the process. Solid para-formaldehyde may beemployed.

The above examples are merely illustrations of conditions for carryingout my process. The reaction conditions may be varied and the aboveexamples are not to be construed as limiting my passed in catalyticcontact through a catalyst 13 invention. For example,themo1e ratio 0: sem.

dehyde to formaldehyde, while generally kept within the range of from5-0.5, may be varied outside of these limits. The high ratio isdesirable because the yield based on formaldehyde is smaller than theyield based on acetaldehyde, and I have found that a more completeutilization 15 the formaldehyde could be obtained by using a higherformaldehyde to acetaldehyde ratio.

The space velocities for the formation of acrolein may vary according toconditions and reaction equipment. I have found a range from 200-3000 tobe suitable for carrying out my reaction. I may define space velocity acubic feet of reactants fed per cubic foot catalyst per hour--volumes'of reactant materials measured at temperatures and pressures ofreaction. As

already indicated, the temperature range may vary from about 200 C. to400 C. While we prefer to carry out the reaction under atmosphericconditions, it is possible to carry-out the reaction under either higheror lower pressures.

While my process is particularly adapted for the preparation ofunsaturated aliphatic aldehydes as described in the above examples, myinvention has wider applications and embracessimilar procedurefor theformation of other mixed products. An example of the formation of anunsaturated aldehyde with an even number carbon atoms is the reactionbetween formalde' hyde and propionaldehyde to form a methacryii--aldehyde.

It will be observed that by my process of react ing with formaldehyde,aldehydes of higher 1110- lecular weight than acetaldehyde, there may beobtained an alkyl group in the alpha position. Such a-substituted typ ofcompound has value in synthetic resin production and other similar uses.For a further example, formaldehyde combines with normal butyraldehydeto form aethacrolein in accordance with the following equation:

CzHs

Thus I have discovered a process which will form any of the substitutedacroleins in which I may be interested.

This reaction of formaldehyde with other aldehydes higher thanacetaldehyde goes with greater ease and with higher yields than producedin the manufacture of acrolein by the afore-described reaction offormaldehyde with acetaldehyde. The catalyst does not become foul orlose its activity to any great degree even with extensive use in theseprocesses for reacting formaldehyde with 3-carbon atom, 4-,carbon atomor higher aldehydes.

My process does not require the utilization of high pressures which isbelieved to be unusual for a process of this type. My process is alsopar-- ticularly desirable from the standpoint that any by-productsproduced are few in number and in relatively small quantities when myprocess is properly employed. Any unreacted components may be reutilizedby circulation through the system.

It is therefore apparent that while I have described my invention insome detail, there are many changes that may be made therein withoutdeparting from the spirit of the invention.

What I claim as my invention and desire'to secure by Letters Patent ofthe United States of America is:

1. In a process for producing unsaturated allphatic aldehydes, the tepwhich comprises reacting materials containing formaldehyde with anotheraliphatic aldehyde, in the presence of a lead acetate catalystmaintained at a temperature greater than 200 C. and less than 400 C.

2. The chemical process which comprises reacting formaldehyde andanother aliphatic aldehyde in the vapor phase and in the presence of alead chromate catalyst maintained at a temperature between 250 C. and400 C.

3. A process for producing higher aliphatic aidehydes, which comprisesreacting a mixture containing at least two difierent aliphatic aldehydesin the vapor phase and in contact with a catalyst comprising a gelcatalyst support and lead chromate, said catalyst being maintained at atemperature at least part of the time, whereby the reaction will takeplace under vapor phase conditions.

4. The process which comprises reacting at least two different aldehydesin the vapor phase and in contact with a catalyst essentially com- 3prising a support and 2.5% to 15% of a lead com- 30 sulphate, leadnitrate,

lead oxide,

pound from the group consisting of lead acetate, lead chromate, andmaintained at a temperature at least part of the time whereby thereaction will take place under vapor phase conditions.

5. The process for reacting formaldehyde with another carbonyl compoundhaving not more than 4 carbon atoms in the molecule, which comprisespassing the aforementioned reactants in the vapor phase and at a spacevelocity within the range of from 200 to 3000, into contact with acatalyst comprising a support and 5% to 15% of a compound from the groupconsisting of lead acetate, lead sulphate, lead nitrate, lead chromate,and lead oxide, such reaction being carried out at a temperature between220 C. and 400 C.

6. The process for reacting formaldehyde with another carbonyl compoundhaving not more than 4 carbon atoms in the molecule, which comprisespassing the aforementioned reactants in the vapor phase and at a spacevelocity within the range of from 200 to 3000, into contact with acatalyst essentially comprising a content of at least one of the leadcompounds from the group consisting of lead acetate, lead sulphate, leadnitrate, lead chromate, and lead oxide, such reaction being carried outat a temperature between 220" C. and 400 C.

'1. The process which comprises reacting formaldehyde with anothercarbonyl compound hav ing not more than 4 carbon atoms in the molecule,in the vapor phase and in contact with a catalyst essentially comprisinga support and a lead compound from the group consisting of lead acetate,lead sulphate, lead nitrate, and lead oxide, said reaction C. and 400.C.

JOSEPH H. BRANT.

